Americans overwhelmingly support labeling foods that have been genetically modified or engineered, according to a New York Times poll conducted this year, with 93 percent of respondents saying that foods containing such ingredients should be identified.

Three-quarters of Americans expressed concern about genetically modified organisms in their food, with most of them worried about the effects on people’s health.

Thirty-seven percent of those worried about G.M.O.’s said they feared that such foods cause cancer or allergies, although scientific studies continue to show that there is no added risk.

Among those with concerns, 26 percent said these foods are not safe to eat, or are toxic, while 13 percent were worried about environmental problems that they fear might be caused by genetic engineering.

Nearly half of Americans said they were aware that a large amount of the processed or packaged foods they now buy at the grocery store contains genetically modified ingredients. And although just a handful of G.M.O. crops are on the market, about 4 in 10 respondents said they thought that most or a lot of their fruits and vegetables were genetically modified.